gt-40 sparkplugs

[surroundsound64]

i don't think 763's are available anymore. i think they've changed to 764's.

autolite has different types of 764's, they have platinum ones, double platinum, and "racing" i think. the only difference is the electrode. i know when i used to run better plugs in my motorcycle, it would run better. what do you guys think about those?

i have been running NGK plugs, but after reading about issues, i decided I need to change back

thanks

I've always liked NGK plugs. Except on Kawasaki engines. For some reason those never get along.

The performance level of spark plugs usually has to do with how far they stick into the cylinder. The longer the plug, the hotter it runs.

[EchoLodge]

So.... Can I run 764 instead of 763? Or go with ths aws22?

[ag4ever]

The longer the plug, the hotter it runs.

Actually, it is not how far it sticks into the cylinder, but how far the ceramic insulation is recessed in the plug.

[surroundsound64]

The longer the plug, the hotter it runs.

Actually, it is not how far it sticks into the cylinder, but how far the ceramic insulation is recessed in the plug.

You are right about the insulation, it does play a big role in the temp to the temp... but the length of the plug is is also a major contributor. In AVTC 2344 we talked allll about spark plugs.

Champion came out with the temperature scale of 26-50. 26 is the lower temperature, on up to 50.
The shorter the plug, the quicker it can dissipate the heat through the cylinder head. Also, the shorter the plug, the less mass it has, therefore less material to get hot, ultimately resulting in a cooler plug.

[dyoungman1]

This post says to use the Autolite 764, but if you enter the Motorcraft number AWSF22C on the Autolite website to cross over, it comes up with the Autolite 103? The only difference I could see between the 764 and the 103 was the heat range. Is that correct?

Is the 764 the one to use?

[east tx skier]

Not a Nautique, but I've got a carbureted 351W HO/GT40 and have had great success running the AL 764s in it.

[boatech]

i use only motorcraft. i recomend every 500hrs. every yr is insane.

[bchesley]

Insane? Come on its only 10-15 dollars to buy a set. I like knowing they are fresh at the first of the season. Heck most of us look for something to do on our boats. Plugs are just one of the easy things......

Brad

[KaNi]

I just bought the 764's today but I got copper ones.....should I put in the plats or are the copper ones aright too?

[TRBenj]

The copper ones are just fine. They should actually outperform the platinums, but wont last as long. I use the coppers and replace them every spring.

[KaNi]

Thanks TRBenj....Do you gap them when you bu them? My buddy said they come pre gapped but i saw earlier on the thread the have to be gapped to .045. Thanks again

[TRBenj]

Thanks TRBenj....Do you gap them when you bu them? My buddy said they come pre gapped but i saw earlier on the thread the have to be gapped to .045. Thanks again

Im not sure what the 764's are gapped at out of the box, but it could very well be .045. I regap mine to .055 since I have an upgraded ignition. Either way, it only takes a second to check them (and change them if necessary).

[MNSuperAir]

Alright, who was the person who outbid me on ebay this afternoon. I got outbid in the last minute of an auction for 24 764's for $25 shipped.

[darrel409]

Mine came pre gapped at .045, got at the local auto parts $12 for all 8.

[Rick]

I honestly think taking them out and checking them at oil change is a great idea. That way you can keep the corrosion to a minimum and make sure you don't have a cylinder going down or an injector problem. If not anually I thing once every 2-3 years would be a good idea. The plugs don't go bad that often but if they corrode in place they will be a b***ch to remove.